You might be a number-cruncher all day, but deep inside you can hear a
little voice that says you really could be making movies. Forget the
ergonomically correct chair that you sit in all day: You want one of those cool
director's chairs with your name stitched on it. Well, that computer on your
desk could be your ticket into the world of movie-making. Editing words, images,
and audio on a computer are all common tasks.You could edit video, output it
straight to tape, and distribute it to all your clients and friends.
It sounds easy, but you probably haven't made your first movie because
television-quality video is a tremendous data-hog. Each frame of digital video
has a resolution of 720 x 480 pixels, and you need 30 frames-per-second (FPS).
If you want to record video straight to your hard drive, you'd need an
audio/video (A/V) drive that's capable of sustaining a data rate of more than
20MB-per-second (MBps). Right now, those don't exist. Some of you might think of
throwing together a five- or six-disk RAID system, but that would cost you a ton
of cash.
One thing you can do is compress your data. Then you can record video onto
readily available and relatively inexpensive hard drives. However, there is
generally a trade-off between the amount of compression and the quality of the
image: You'll need a dedicated capture board if you want real television-quality
video.
Perception Video Recorder
Digital Processing System's Perception Video Recorder (PVR) is a
high-quality product for recording and playing back video. It runs under Windows
or Windows NT, on both Intel Pentiums and Digital Equipment Alpha CPUs. PVR is
able to squeeze exceptional-quality video out of your computer because it uses
an optimized version of the Joint Photographic Experts Group (JPEG) compression
scheme.
PVR is a full-length PCI card. If you want to grab video, you'll need to
add the video-capture daughter card. This daughter card extends enough to
effectively take up an extra slot. PVR doesn't record or play back audio,
although it supports a number of audio boards. The card also has its own SCSI
controller to allow connection of PVR's dedicated hard drives: These drives are
not system drives, but they are devoted to PVR. There are two connectors on the
back, one for input and one for output. Each connector is a little octopus of
cables with connections for sync, composite video, S-Video, and component video.
This makes PVR a perfect match for the BetacamSP video format, the current
high-end standard for applications such as corporate video and broadcast news.
Don't confuse BetacamSP with the old BetaMax standard that VHS wiped off the
face of the earth. BetacamSP is a whole different beast, and it's recently
become more affordable with decks now in the $7,000-$10,000 range.
PVR's software is straightforward. You play animations using a VCR-type
control panel. If you want to create a clip from a series of animation frames,
you simply choose Open from the pull-down menu, select the frames, and hit OK.
Most of PVR's operation is this easy.
PVR is basically a high-quality digital VCR, but it has a number of goodies
thrown into the mix. For example, you can convert PVR clips for use with Adobe's
Premiere software package. There's a complete set of diagnostic and file
management utilities and useful graphics, including color bars, to fine-tune
your video setup. You can also perform a number of effects in real-time, such as
playing a clip in black-and-white or playing a clip at film's 24 FPS speed
instead of video's 30 FPS.
PVR has a number of quality settings you can choose from. If you're
creating digital video for a CD-ROM or multimedia application, you can capture
acceptable quality at a 2MBps level. For broadcast-quality animation, you might
want to use "Broadcast level" (5Mbps) or "Digital level"
(6MBps). You should be aware that even fast A/V hard drives can't always
maintain 5-6MBps levels across the entire drive's surface. If you're using
6MBps, you might be able to use only a third of the drive's capacity. If you're
working with longer segments of video, DPS suggests you use the 4MBps setting
because it can be maintained across the entire drive. PVR software also includes
a utility for testing your drive's performance.
Running PVR under Windows NT offers a couple of useful advantages over
non-NT operating systems: PVR's SCSI drives are invisible to the system without
NT. If you use NT, your animation and video sequences are not only visible, they
are accessible to any application in a variety of file formats.
This offers you an advantage when you record animations. On non-NT versions
of PVR, the animation program needs to save the frames to a system hard drive.
You then import your frames into PVR. If you work on NT, you can save the frames
straight to PVR, and you don't need to have a few hundred megabytes of free
space on your system drives.
PVR has some basic editing capabilities: You can arrange your clips in any
order, choose in-and-out points, and create simple cross-fades and dissolves.
It's a rudimentary editing package, but you can use it to put together simple
projects, such as a demo reel, quickly and easily. It also adds a tremendous
amount of creative freedom, especially for animators: You can cut up and
rearrange your longer animation sequences to create a new look or feel for an
animation while the client watches.
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